San Joaquin Assistant Sheriff John Huber is retiring, proud of a 31-year career full of accomplishments. But bothered by one unsolved murder more than any other.

Huber worked homicide in March of 1995 when two scavengers out in the Delta dragged an abandoned refrigerator out of the mud. Inside was a corpse.

"The lady in the fridge," Huber said.

He went out to Bacon Island Road. The refrigerator, a gold Frigidaire, had been roped shut. Stuffed in the bottom compartment was a woman, killed by blunt trauma to the head.

Forensic analysis determined she had probably been there since summer 1994. Almost a year. Corpses sealed off from air turn to a sort of wax by a process called adipocere; turning to soap, some detectives call it.

"It almost looked like she was a mannequin," said Huber. "She was hard, like Styrofoam."

The waxen woman was white, strawberry blonde, 110 to 130 pounds, age 29 to 41 - decomposition prevented more accuracy - and packed in with blankets and a sleeping bag. Her hands were tied behind her back. Her mouth was gagged with a sock, taped over with black electrician's tape. The right front temporal lobe of her skull was caved in.

He found no ID on her. But clues abounded. "I was absolutely positive I was going to ID this girl in the first week or so," Huber said.

From the refrigerator's serial number he learned it had been manufactured in Pittsburgh, Penn., in the 1980s and sold in Oakland.

But no one returned the warranty.

Up top, the freezer compartment contained several butter packets from Kentucky Fried Chicken; five small school-like milk cartons; an ice bag from Glacier Ice.

Small cartons of Crystal brand milk, he learned, were distributed from Sacramento only to Northern California institutions such as schools and jails.

From the ice bag's manufacturer date he learned it was from a lot shipped to liquor stores, bait shops and marinas in cities such as Antioch and Discovery Bay.

The evidence pointed to an East Bay/Western Delta woman, divorced, or engaged once but no longer.

Not a prostitute, dope fiend or drifter. A free spirit, maybe. But a woman who belonged somewhere. "I think she's somebody that somebody would miss," Huber said. "Kind of a hippie girl. Somebody who would go to Renaissance faires or craft fairs and go hiking."

He had her dental work charted. Thousands of possible matches in the Department of Justice database provided no match.

He sent a teletype to missing person databases. Thousands of hits came back. "I literally have gone through maybe a total of 5,000 women."

He created Northern California map overlays: Blue dots for milk distribution spots, green for ice spots, yellow for tape spots. They converged only in the East Bay/Western Delta.

He called schools and correctional institutions: "Do you have an employee that recently stopped showing up to work?"

He visited area dentists: "Do you have a patient who came in regularly to have her teeth cleaned?"

He got newspapers and TV stations to do stories. "I did everything imaginable on this."

But he never identified her.

When he got promoted - the solve rate in his homicide division was above the national average - he took her file upstairs with him. He worked it when time allowed.

"If you could name her, I think you could solve the case," he said.

"But if it's the husband, the boyfriend - the girlfriend, if she's of that persuasion - they're not going to report her," Huber said. "And should a neighbor say, 'Hey, where did Jane Doe go?' he's going to say, 'Hey, she ran off over a boyfriend and I never saw her again.' "

It gnaws at him. "It's very frustrating not to solve any homicide case. I don't care if it's a prostitute or people well-off. Everyone deserves to be worked as hard as you can work it, as long as you can work it.

"And you should never give up."

He retires at the end of the month. Only last month he surrendered the case of the lady in the fridge.